Device for discharging lump or viscous material,particularly wood chips,from the lower part of an upright container



United States Patent Inventor Veikko Johannes Hyttinen Eskilstuna, Sweden Appl. No. 750,233 Filed Aug. 5, 1968 Patented Nov. 17, 1970 Assignee Sunds Aktiebolag Sundsbruk, Sundsvall, Sweden Priority Aug. 16, 1967 Sweden 1 1,496/67 DEVICE FOR DISCHARGIN G LUMP 0R VISCOUS MATERIAL, PARTICULARLY WOOD CHIPS, FROM THE LOWER PART OF AN UPRIGHT CONTAINER 16 Claims, 7 Drawing Figs.

US. Cl 214/17; 222/410 Int. Cl B65g 65/48 Field of Search 214/17.8; 222/410, 412

[56] References Cited UNITED STATES PATENTS 439,773 11/1890 Cole 222/412X 2,601,534 6/1952 Laffoon 222/410X 2,612,298 9/1952 Wearne 222/410 2,767,884 10/1956 Gross 222/410X Primary Examiner- Robert G. Sheridan Attorney- Pierce. Scheffler and Parker ABSTRACT: A device for discharging comminuted material such as wood chips or slurries thereof from the bottom of a container therefor in which the base of the container includes a rotating bottom element having vanes for moving material at the bottom of the container radially to the periphery of the rotating bottom element for discharge from the container and also in which means are provided for imparting movement to the material after it has been discharged from the container to facilitate further transportation of the material and to prevent clogging of the outlet.

Patented Nov. 17, 1970 3,540,604

Sheet 1 014 Patented Nov. 17, 1970 3,540,604

Sheet 2 of 4 Patented Nov. 17, 1970 3,540,604

Sheet 4' of4 DEVICE FOR DlSCI-IARGING LUMP R VISCOUS MATERIAL, PARTICULARLY WOOD CHIPS, FROM THE LOWER PART OF AN UPRIGHT CONTAINER When discharging material having a high internal friction, in lumps or viscous material, such as wood chips and the like, through an outlet situated at the lower portion of an upright container, problems arise because of the material easily clogging at the outlet, thereby blocking the latter. The speed of sinking of the material within the container may also vary in the cross-sectional area thereof by the material being braked on account of the friction with the walls of the container. Another difficulty in this connection is how to provide for a uniform speed of discharge.

The present invention has for its object to overcome the above mentioned drawbacks and relates to a device for discharging lump or viscous material, preferentially cellulosic fiber material, for example, wood chips, from an upright, preferentially cylindrical container, which is open, preferably entirely open, at its bottom, i.e. the same lacks a stationary bottom, there being provided, instead of the bottom, a substantially horizontal loose bottom adapted to cooperate with the lower portion of the container and adapted to turn on a vertical or substantially vertical shaft, said loose bottom, all the way around, extending up to the zone at the peripheral portion of the container and through which material, present within the container, is meant to be discharged from the container. The essential novel characteristic feature of the device consists in that the loose bottom, which is nonforaminous, is, on its surface facing the interior of the container, provided with a number of guide members, adapted, upon rotation of the loose bottom, to impart to the lowermost layer of the column of material in the container, said layer resting on said bottom, a continuous lateral movement on said bottom, the column of material at the same time moving uniformly downwards along the entire cross-sectional area of the container. The guide members consist preferentially of edgewise arranged, preferably substantially vertical vanes, each individual vane, or several vanes together, extending radially from the center portion of the loose bottom to the periphery of the loose bottom and forming channels which are open upwards.

These and other characteristic features of the invention will appear from the following detailed description, in which reference is made to the accompanying drawing FIGS.

FIG. 1 shows a vertical sectional view of'one embodiment of a discharging device according to the invention, connected to the lower portion of an upright container for material, FIG. 2 showing a plan view of the discharging device proper with ad jacent parts. FIGS. 3 and 4, in a corresponding manner, show a vertical sectional view and, respectively, a plan view of a modified embodiment of the loose bottom and the guide members, FIGS. 5 and 6, likewise showing a vertical sectional view and, respectively, a plan view of one embodiment of the loose bottom, in which the bottom has a conically curved surface and the guide members have furthermore changed shape and extension, which also applies to the bottom portion of the container in which the loose bottom is positioned. FIG. 7, finally, shows an embodiment, similar to the one appearing from FIG. 1, but in which the lower portion of the container is of a different shape.

In FIG. 1, numeral 1 indicates part of the lower portion of an upright container, into which material is to be fed from above. At its upper end said container may be open or closed and the material may be dry or enclosed in treatment liquid. The cross-sectional area of the container I normally is circular but it may also be of some other shape, for example, quadratic. The walls of the container may be vertical or inclining so that the cross-sectional area of the container increases downwards, by which the friction between the downward horizontally on a centrally positioned, vertical shaft 5. The shaft 5 is joumaled in a bearing 6 and extends through a packing 7, provided in the wall of the container. The shaft is turnable by means of a motor 8 and gear means 9. The bearing 6 is supported by a bracket 10, a star wheel or the like. The loose bottom 2is meant to support the column of material so that the lowermost portion 3 of the container 1 is unloaded and can be kept only partly filled.

On the upper side of the loose bottom 2 there are provided edgewise placed, preferably substantially vertically arranged discharge vanes 11, 12, which, when the loose bottom 2 is being rotated feed that layer of the column of material which is between the loose bottom and the upper edges of discharge vanes 11, .12. The feeding takes place substantially radially outwards. The vanes 11, 12, which are to be considered as guide vanes, may be of varying heights and curvatures, depending on the properties of the material and the quantity of material to be discharged per unit of time. The speed of rotation, at which the loose bottom 2 is to be rotated, may be varied in order to control the speed of discharge of the material and it is, in general, low, about 0.5--20 r.p.m., preferably l- -6 r.p.m. and preferentially about 2-3 r.p.m. when chips are being discharged. The discharging is facilitated thereby that the material, which exerts a pressure on the wall of the container, has a tendency to fall down through the vertical slot between the lower edge of the wall of the container and the loose bottom. In order to prevent such uncontrolled falling down of the material the loose bottom is, in general, embodied with a larger diameter than that of the portion of the container located above the loose bottom. The difference in diameter, the height of the slot and the conicity (the cone angle) are adapted to the nature of the material. For the further transportation of the material falling down into the conical portion 3 of the container 1 there are, at the wall of the container and level with, or immediately below, the loose bottom 2 provided tangentially directed nozzles 13, through which liquid is pumped in. Thereby the material is mixed with the liquid and is given a rotary motion, which facilitates the discharging and prevents the formation of plugs in the outlet.

The embodiment according to FIGS. 3 and 4 differs from the preceding embodiment in respect of the shape of the loose bottom, which is embodied with a horizontal, plane upper surface 14, and in respect of the guide vanes, which are embodied flowing material, being treated, and the walls is reduced. In

the lowermost portion of the container there is provided a slightly conical loose bottom 2 and below the latter the container is embodied with a conically tapering portion 3, ending in a pipe socket 4. The loose bottom 2 is adapted to turn as coherent bows 15, extending from a central cone to the periphery. This embodiment of the guide vanes may, of course, be used also in connection with a loose bottom of conical shape (FIGS. 1 and 2).

In the embodiment according to FIGS. 5 and 6 the difference, compared to the previous embodiments, resides therein that the loose bottom has a conically curved surface 16 and in that the guide vanes 17 have another shape and extension (FIG. 6). The lower portion 18 of the container 1 has a circular cross section and has its bottom surface 19 embodied as an end wall of a pressure vessel. The discharging of the material takes place through a tangentially positioned outlet 20.

The embodiment according to FIG. 7 differs from the embodiment according to FIG]! in respect of the shape of the lower portion of the container 1, in which the loose bottom is indicated by 21. The vanes provided on the bottom 21 are indicated by 22 and 23,. The upper bearing 6 of the vertical shaft 5 is fixed to a conical plate member 24, which in its turn is welded to the bottom of the container. Hereby a reduced resistance during the rotation of the suspension of material is obtained, because supporting brackets, star wheels or similar members for the bearing 6 are dispensed with. 25 indicates a discharge pipe, extending preferably tangentially.

As has appeared from the drawings the shapes and extensions of the guide vanes may vary. The vanes may (as shown) be curved but they may also be straight. Furthermore, a number, preferably two, three or more vanes of substantially the same shape may extend radially, when counting from the central portion of the loose bottom to the periphery thereof,

or also said distance may be covered by a plurality of vanes, for instance two '(11 and 12 of H0. 2). In the aforementioned embodiments the vanes may be connected directly with each other at the central portion of the loose bottom or at a conical or cylindrical part provided at said place. Also, they may end at a distance from the central portion and/or the cylindrical portion. The loose bottom is, in a vertical sectional view, shown to be plane or conical with straight or concave generatrices, which, however, does not exclude an embodiment having convex generatrices. It is possible also to embody the loose bottom with such a small conicity (cone angle) that the generatrix, instead of being directed substantially horizontally, is directed slantingly downwards, and so slanting that the directionis more vertical than horizontal. The extension of the loose bottom in the radial direction may also vary. In the embodiments shown the loose bottom has a larger diameter in the horizontal plane than has the inner and/or outer diameter of the container. The loose bottom may, however, have the same diameter as, or a smaller diameter than, the above-mentioned container diameters. Within the discharge chamber proper there may be provided screw discharging means.

lclaim:

1. A device for discharging cellulosic fibrous material such as wood chips and cellulose pulp from a substantially vertical container having a substantially uniform cross-sectional area throughout its length and being open at the bottom thereof, comprising a substantially horizontal bottom element disposed at the bottom of said container and rotatable in a substantially horizontal plane, said rotatable bottom element extending radially to a point spaced from the peripheral bottom edge of said container to provide an annular slot at said peripheral bottom edge of said container for discharge of material from said container, said rotatable bottom element being nonforaminous, aplurality of discharge vanes rigidly mounted on said bottom element and adapted, upon rotation of said bottom element, to continuously move the lowermost layer of material in said container which rests on said bottom element laterally and radially to said annular slot for discharge from the container so that the material within the container will descend therethrough substantially uniformly across the entire cross-sectional area thereof, a discharge chamber secured beneath the container for receiving the material discharged at said annular slot and outlet means from said discharge chamber.

2. A device as claimed in claim 1, wherein said rotatable bottom element is conical in an upward direction, has a straight generatrix, and extends substantially in the horizontal direction.

3. A device as claimed in claim 1, wherein said rotatable bottom element is conical in an upward direction, has a curved gen eratrix, and extends substantially in the horizontal direction.

said rotary bottom element is larger than the outer diameter of the container.

5. A device as claimed in claim 1, wherein said discharge vanes are arranged edgewise, are substantially vertical and extend substantially radially from the center of said rotatable bottom element to the periphery thereof, so as to form channels which open upwardly, the height of said discharge vanes at the periphery of said bottom element, being less than the height of the annular slot at the periphery of said container.

6. A device as claimed in claim 3, wherein said discharge vanes extend from the central portion of said bottom element to a point inside the periphery thereof, the height of said vanes being less than the height of the annular slot at the periphery of said container.

7. A device as claimed in claim 3, wherein said discharge vanes are situated at the intermediate portion of said bottom element, when viewed in the radial direction, the height of said vanes being less than the height of the annular slot at the peripher of said container 8. A evice as claimed in claim 3, wherein said discharge vanes are situated on the outer portion of said bottom element, when viewed in the radial direction, the height of said vanes being less than the height of the annular slot at the periphery of said container.

9. A device as claimed in claim 1, wherein said discharge chamber has a downwardly decreasing cross-sectional area and merges into said outlet means said outlet means extending laterally thereof.

10. A device as claimed in claim 1, wherein said discharge chamber is provided with dilution nozzles for facilitating the discharge of material through said outlet means.

11. A device as claimed in claim 10, wherein said dilution nozzles are directed substantially tangentially.

12. A device as claimed in claim 1, and further comprising means for pressurizing said discharge chamber.

13. A device as claimed in claim 1, wherein said discharge chamber includes a cylindrical shell wall and a rounded dishshaped bottom portion and wherein said outlet means is disposed tangentially on said cylindrical shell wall.

14. A device according to claim 1, wherein said discharge chamber-comprises a body having a substantially elliptical cross section and wherein said outlet means is disposed tangentially at substantially the level of the major axis of the ellipse.

15. A device as claimed in claim 1, wherein said discharge chamber is wider than the base of the container.

16. A device as claimed in claim 1 and further comprising a sleeve extending upwards through the bottom of said discharge chamber, a bearing in said sleeve and a rotatable shaft extending through said bearing, said rotatable bottom element being supported and rotated by said rotatable shaft. 

